In many fluid systems, such as power transmissions, there is a need to transfer hydraulic fluid between adjacent components which are movable relative to each other to a slight degree. For example, a fluid transfer tube might be located between a transmission control housing and the main transmission housing or between the control pump and one or more elements within the transmission casing. These elements do not move relative to each other during power transmission; however, their alignment is somewhat indeterminate during assembly. Therefore, the passages are not always perfectly aligned longitudinally.
To accommodate this misalignment, it is common practice to use a composite tube having an oversized inner diameter which will seal at a diameter substantially greater than either of the passage diameters such that the misalignment of the components is within this overlapped degree and therefore are sealed in assembly to prevent leakage. However, this does require significantly more material within the construction of the tube than is actually required if the passages are not misaligned.
The prior art tubes are a composite structure having rubber components molded about a rigid component in a manner that will permit the rubber components to seal against the surfaces of the two transmission components which contain the passages between which the fluid is transferred.